@inproceedings{irwin1983on,
title={On the vanishing of and spanning sets for Poincaré series for cusp forms},
author={Irwin Kra},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203302541616357},
booktitle={Acta Mathematica},
volume={153},
number={1},
pages={47-116},
year={1983},
}
Irwin Kra. On the vanishing of and spanning sets for Poincaré series for cusp forms. 1983. Vol. 153. In Acta Mathematica. pp.47-116. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203302541616357.